﻿// Copyright 2008 Chris Varley (http://www.contractdriven.net/)
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

using System;

namespace ContractDriven
{
    public interface IAssertion
    {
        /// <summary>
        /// <para>A message to display if Eval() returns false.</para>
        /// <para>This is formatted using string.Format(), so you can specify variable placeholders such as {2} within the string</para>
        /// <para>The parameters passed to string.Format() function should be the Args property.</para>
        /// </summary>
        string FailureDescription { get; }

        /// <summary>
        /// Performs the check for the guaranteed state.
        /// </summary>
        /// <returns>'true', if the assertion is true, 'false' if the assertion is false.</returns>
        bool Eval();
    }
}
